Fluorescence imaging involves a fluorophore marker or tag that emits light at an emission wavelength in response to interacting with light at an excitation wavelength. Conventional fluorescence imaging systems may include optical arrangements such as off-axis illumination and folded illumination with a dichroic optical element. However, both approaches require considerable volume and thickness (along the optical axis) to separate light at the excitation and emission wavelengths. The off-axis illumination arrangement uses this volume and thickness to angularly separate the two wavelengths and the folded path arrangement uses a dichroic optical element, which may utilize considerable thickness along the optical axis.